Laser Components GmbH has expanded its Count series single-photon-counting modules to include the new Countblue devices. They combine the low count rates of the existing modules with higher detection efficiencies at shorter wavelengths. More than 60% of incoming photons can be detected at 405 nm, more than 65% in the green, and more than 50%, typical, in the red. The semiconductor design ensures stable count rates and zero bi-stability. The good short-wavelength performance makes the modules suitable for use in fluorescence spectroscopy and analysis, time-resolved single-molecule detection, particle sizing, astronomy, lidar and confocal microscopy. The modules feature the same robust design as the earlier ones and are mechanically compatible with other commercially available photon-counting modules.